ecsscr



Patented Jan. 2, 1923.

' 1 UNITED srsrr J SIDNE M.-

.PATENT OFFICE.

CADWELL, 0F LEONIA, NEW JERSEY, ASSIGNOR TO THE NAUGATUCK CHEMICAL COMPANY, A CORPORATION OF CONNECTICUT.

PROCESS FOR VULCANIZING RUBBER AND PRODUCTS OBTAINED THEREBY.

No Drawing. Original application filed April 1, 1922, Serial No. 548,828. Divided and this application filed April 1, 1922. Serial No. 548,830.

To all whom it may concern Be it known that I, SIDNEY M. OAnwnLL, a citizen of the United States, residing at Leonia, county of Bergen, and State of New Jersey, have invented certain new and useful Improvements in Processes for Vulcanizing Rubber and Products Obtained Thereby, of which the following is a full, clear, and exact description. 7

This invention relates to vuleanizing rub- "ber and similar materials and products ob tained thereby, being more particularly directed to acceleration of vulcanization by a class of organic accelerators and products resulting from such vulcanization.

This case is a continuation in part of application Serial No. 379,492, filed May 7, 1920 and a'division of application Serial No. 548,826, filed April 1, 1922.

One object of the invention is to provide a process of the kindmentioned employing accelerators obtainable from inexpensive raw materials by a simple method. An-

other object of the invention is to provide a process in which accelerators oi the kinc mentioned may be readily compounded with rubber, orsimilar material, which shall permit oi the carrying out of vulcanization at ordinary temperatures, in masses of rubber or in thin sheets, while avoiding the generation of acids durin the process of vulcanization, as, for examp e, takes place when sulphur chloride is used. Another object is to provide a series of products having generally hysical characteristics, such as strength, resistance to aging, etc., and which shall be substantially free from the odor of the vulcanizing ingredients employed. Other objects will in part be obvious and in part pointed out hereinafter.

desirable high tensi e resistance to flexing,

The invention accordingly consists broadly in the process, and product obtained theretrom, for treating rubber and similar materials, which comprises subjecting the rubher to a vulcanizing agent and a substance containing the radical RCSM,

and vulcanizing the rubber. In this formula, It represents any element subject to the limitation mentioned hereinafter; M represents a salt-iorining eiement or group or hydrogen, such as zinc, animon1um,.etc., and is designated as representing a metal or being metallic, or a radical sen or a radical and X represents any bivalent element or radical, such as sulphur, oxygen, etc, subject to the limitation mentioned later.

It will be seen that the substances con taining the radical fall intothree groups corresponding to the three said significations of M. In the first two groups the symbol R in RGSM is limited to any element except nitrogen; in the third group where M represents a a i this limitation is absent. In the table herein shown forming part of the specification,

there is shown the broad group containing the radical RCSM,

subdivided into three smaller groups which are respectively RCSM, RICSSCR, RCSIGR.

M=Meta1, M son M=OR etc.

under which fall RCSM,

where M is the metal and thiol salts are included, and

RCSSCR,

where M is equal to SCR it x and the disulphides are represented. The formula RCSCR ltlt represents monosulphides which may be regardedas thioi acid anhydrides. R in these formulae designates any element except nitrogen.

1n employing the first group of those men tioned above including substances having the formula RCSM,

it has been found that M preferably represents either zinc or mercury in the mercuric state when vulcanization at ordinary temperatures, approximately 70 F., is carried out, and when vulcanization above ordinary temperatures, the preferred metals are the following :zinc, mercury, preferably in the mercuric state, lead, preferably in the plumbous state, cadmium, copper, preferably in the cupric state, arsenic, preferably in the arsenous state, manganese, preferably in the manganous state, so that the preferred formula for the thiol salts is RTIISM where M represents one, of the preferred metals given. M may be substituted by any metal provided that one of the metals just mentioned is present in theeombination either at some other position in the formula including a low or be introduced otherwise than as part of this compound. In connection {with the other groups mentioned, namely, those represented by the formulae R'rssCR and "RCSCR constituting respectively the disulphide "and monosulphide groups, the presence of zinc or mercury in the mercuric state is preferable when vulcanization at ordinary temperatures is carried out. When vulcanization above ordinary temperatures is carried out the preferred metals are the following zinc, mercury, preferably in the mercuric state, lead, preferably in theplumbous state, cadmium, copper, preferably in the 'cu'pric state, arsenic, preferably in the arsenous state, manganese, preferably in the manganous state. As not'ed'in connection with the first group, the metals employed with groups 2 and 3 may be present in any combined form.

In the table mentioned above, R and X are shown as represented by carbon, oxygen, nitrogen and sulphur, which are four of the more important elements occurring in organic compounds.

It will be understood that the invention is not limited to the species shown in the accompanying table, and that by substituting other elements than nitrogen, carbon, oxygen and sulphur for the symbol R or X, various other species may be formulated falling within the scope o'f'the invention.

Although the "various species disclosed are represented as symmetrical, it willbe understood that unsymmetrical'species also fall within the limits of the'invention.

The table is ing GROUP 111. -ncs'cn M: pa

t Mon'os'til'p'n'ides.

in general it is tobeno'ted in connection with members of this group thatetheyeareable to accelerate both hot vulcanization, that is, vulcanization at or aboveQO F. and vulcanization below such temperatures and that they may beused'for such vulcanization in thick masses of rubberyin thin sheets, or in cements. They are'y particularly adapted for accelerating hot vulcanization. Although active as accelerators they exhibit substantially no tendency" to cause prevulcanization or burning by milling.

The general procedure-for vulcanizing employing members of this group is as follows :100 parts of rubber, 10 parts of zinc oxide, 3 parts of sulphur, and 0.13.0 parts of the accelerator are mixed. If7vuleanization with heat is employed the-usual temperature or lower is used for periods of thirty minutes or more to completevulcanization. The normal or usual temperatures of hot vulcanization are240 F. or: above. Where vulcanization at ordinary'room temperature, approximately F., is desired the mixed materials are allowed to stand at ordinary room temperature for ;approximately one week when vulcanization is complete. In connection with curing at-such temperatures, it is pointed out that the curis effected in a longer time than is required in the use of members of Groups 1 and 2 set forth in my copending applications Serial Nos. 54.8,826, 548,827, 548,828 and 545,829.

The procedure given above may be employed with thin or thick masses of rubber, and in the case of cements where a solvent is used with the mixture, the procedure after mixing and evaporation of the solvent is substantially identical with that-employed for thin masses of rubber. The group possesses the particular advantage that its members may be introduced into bulk rubber with practically no danger 'of prevulcanization orburning when milled. As pointed out above, a combined metal, preferably in the form of a metallic oxide such as zinc oxide, is employed in connection with members of this group. The oxides are generally designated as MQOQM having previously been defined. In general the use of bases, particularly amines, is preferred in connection with members of this group. p

The action of the addition of; primary and secondary amines to materials of this class has been found to be as follows: The

i have "substantially acceleration by aliphatic amines is greatest pound is used. An excess of primary aliphatic amine retards the cure considerably. An excess of secondary aliphatic amine retards the cure less. The greater the amount of primary aromatic amine added, the greater the acceleration. Tertiary amines no effect. Dibenzyl amine hasgiven excellent results in the acceleration of vulcanization according to the invention. Sodium hydroxide also accelerates the action of monosulphides.

Species ccsoc II N O O The following member of this species has been employed to give good results in connection with the process included in the lnvention Thiolbenzoic anhydride C6 6 H G 5 also unsymmetrical compounds occupying grgidway position between species 87 and Benzoylbutylxanthogenate c itanscocni a Benzoylethylxanthogenate ofiizec-scooin5 ll II The Substance thiolbenzoic anhydride and similar substances are set forth and claimed in co-pending application Serial No. 548,831, filed April 1, 1922.

As a specific example of curing below the normal hot vulcanizing temperatures, the following procedure may be carried out: 100 parts of rubber, 10 parts of zinc oxide, 3 parts of sulphur, 2 parts of paratoluidine, and 5 parts of thiolbenzoic anhydride are mixed by milling in the usual manner, and the mixture is vulcanized at 212 F. for 2 hours in open air.

sults and the time of vulcanization may be prolonged without damageto the stock, although, of course, the time of vulcanization will be dependent on the thickness of the goods. The resultant product is odorless and colorless and has the usual excellent properties of rubber cured with sulphur.

The accelerator above mentioned is prepared by dissolving 1 mol oiammonium salt of phenylmethyldithiocarbamic acid in alco-. hol and treating it with moi of bromcyanide, CNB,., dissolved in alcohol; or an alcoholic solution of ammonium phenylmethyldithiocarbamate may be treated with phenylmethylthiocarbamic acid chloride in alcoho]ic solution. Other methods of preparation may be employed and applicant does not limit himself to the methods of preparation of accelerators herein described.

Other members of this class include:

Tetramethylthiurammonosulphide on on 3 NCASGN 3 CH3 u H om Tetraethylthiurammonosulphide Diphenyldiethylthiurammonosulphide,

Tetrapropylthiurammonosulphide a H S Methylphenylethylthiurammonosulphide CeHs N ON 11 0211/ 1 n 011 Phenylmethylcarbamylester methyldithiocarbamic acid of: phenyldisclosed and included in the invention of the present application.

It is to be understood that rubber substitutes, synthetic rubber, balata, gutta percha, etc., ma be similarly treated instead of rubber an it is intended to include such processes in the claims hereto appended.

By the use of accelerators of this group vulcanization is accomplished in a rapid and GfilClGDlJ manner substantially without danger of burning or prevulcanization while milling, and the raw materials used for making the accelerators are inexpensive. The processes themselves are rapid and efficient and easily carried out. The products possess desirable physical characteristics, such as good tensile strength, resistance to aging. resistance to flexing, and in general are free -from the odor oi vulcanizing ingredients.

It will thus be seenthatamong others the objects of the invention above enumerated are achieved. i As many apparently widely diflierent embodiments of this invention may be made without departing from the spirit thereof, it will be understood that I do not intend to limit myself to the specific embodiment herein set forth except as indicated in the appended claims. 1

Each of the substances enumerated herein as members of the various species has been employed in the vulcanization-of rubber and has been found to accomplish vulcanization as indicated.

Having thus described my invention, what i claim and desire to protect by Letters Patent is:

l. A process of vulcanizing rubber or similar material which comprises combining with the rubber a vulcanizing agent and an accelerator comprising the group RC-SCR,

and vulcanizing the rubber.

2. A process of vulcamzlng rubber or s1milar material which comprises combining with the rubber a vulcanizing agent and an ac celerator comprising the group RGSQR it it and vulcanizing the rubber.

l. A. process of vulcanizing rubber or similar material which comprises combining with the rubber avulcanizing agent and an accelerator, comprising the radical NCSCN it it in the presence of a combined metal M, and vulcanizing the rubber. I I 5. A process of vulcamzmg rubber or simi- ;lar materialwhich comprises combining with y in the presence of a combined metal rulcamzmg the rubber.

7. A process of vulcanizmg rubber or similar material which comprises combining with the rubber ,a Vulcamzmg agent. an acceler I i 1 1 u toi compiising tne group and an amine, and vulcanizing the rubber.

8. A process of vulcanizing rubber or simi'- lar material which comprises combining with the rubber a vulcanizing agent. an accelerator comprising the group RCSGR lit in the presence of a combined metal M and an amine, and vulcanizing the rubber.

9. A process of vulcanizing rubber or similar material which comprises combin ng with the rubber a vulcanizing agent, an accelerator comprising the radical NCSC and an amine, and vulcanizing the rubber.

10. A process oi? vulcanizing rubber or similar material which comprises combining with the rubber a vulcanizing agent an accelerator comprising the radical.

NCSGN II II X x in the presence of a combined metal M and an amine, and vulcanizing the rubber.

1-1. A process of vulcanizing rubber or similar material which comprises combining with the rubber a vulcanizing an at. an accelerator comprising the radical I and an amine, and Vulcanizing the rubber.

12. A process 0i vulcanizing rubber or similar material which comprises combining j 13. ,A process of vulcanizing riibber or similar material which comprises combining accelerator comprising the group RCSCR it in the presence of combined Zinc, and vulcanizing the rubber.

li. A process of rulcanizing rubber or similar material whichcomprises combining with the rubber a vulcanizing agent and an accelerator comp *isin'gthe radical NCSCN u n in the presence oit'combined;zinc, and vulcanizing the rubber.

15. A process of vulcanizing rubber or similar material which comprises combining with the rubberfa vvulcanizing agent and an accelerator comprising the radical NCSCN s in the presence of combined zinc. and vul ng the rubber. v

Elie process oi treating) rubber or similar materials comprising combining it with a Yulcanizingv agent and a thiuram monosulpliide, and vulcanizing the rubber.

117. The process oi ti' eating rubber or similar materials comprising combining it with a Vulcanizing agent and an aryl alkyl thiiirammonosulphide, anc vulcanizing the rubber. Y

18. The process of treating rubber or similar materials comprising combining it with a vul anizing agent and a thiurammonosulphide in the presence of a combined metal M. and rulcanizing the rubber.

19. The process of treating rubber or similar materials comprising combining it witl'ra vulcanizing agent and an aryl allryl thiuramnionosulphide in the presence of a combined metal M. and vulcanizing the rubber.

20. The [u'ocess of treating rubber or "similar materials comprising"combining it in. a vulcanizing agent and a thiurammonosulphide in-the presence of combined zinc. and vulcanir/zing the rubber.

21. The process of treating rubber or similar materials comprising combining it with a vulcanizing agent and an aryl alkyl thiuramsulphide in the presence oi. combined zincrand vulcanizing the rubber.

22. The process of treating rubber or similar materials comprisingcombining. it with a vulcanzing agent and a thiocarbamic acid anhydride'.

23. The process of treating rubber. or similar materials comprising combining it with a vulcanizing agent and a' substance having the group p o cyclic-NCSCN-cyclic and v'ulcanizing the rubber.

and vulcanizing the rubber.

25. The process of treating rubber or similar materials comprising combining 100 parts of'rubber, 10 parts of zinc oxide, 3 parts of sulphur and 0.1 part of diphenyldimethylthiurammonosulphide, and vulcanizing the rubber under approximately 40 lbs. steam pressure forapproximately 10 minutes.

26. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and an accelerator comprising the group Boson, ll

27. A vulcanized rubber derived from rubber or similar material combined with a vulcanizingagent and an accelerator com prising the group npgsiin in the presence of a combined metal M.

28. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and an accelerator comprising the radical NCSCN.

29. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and an accelerator comprising the radical NELSEN in the presence of a combined metal M.

30. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing a ent and an accelerator comprising the radical NCSCN. ii

31. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and an" accelerator comprising the radical I NCSCN in the presence of a combined metal M.

32. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent, an accelerator comprlsing the group RGSCR a vulcanizing agent, an accelerator com prising the group Rcspn it in the presence of a combined metal it and an amine.

34-. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent an accelerator comprisin the radical NCSCN l l and an amine. v

35. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent, an accelerator comprising the radical NCSCN ii in the presence of a combined metal M" and an amine.

36. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent, an accelerator comprising the radical NUSCN i t and an amine.

37. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent, an accelerator com prising the radical NGSCN in the presence of a combined metal M and prising the j radical NCSCN ill in the presenceoi combined zinc.

40. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and an accelerator com prising the radical NCSCN l in the presence of combined zinc.

1-1. A vulcanized rubber derived from rubber or similar'material combined with a vulcanizing agent and a thiurammonosulphide.

42. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and an aryl alkyl thiurammonosulphide.

43. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and a thiurammonosulphide in the presence of a combined metal M.

-14. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and an aryl allryl thiurann monosulphide in the presence of a combined metal M.

45. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and a thiurammonosulphide in the presence of combined zinc.

46. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and an aryl alkyl thiurammonosulphide in the presence of combined zinc.

47. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and a thiocarbamic acid anhydride.

48. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and a thioacyl sulphide.

49. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and a substance having the group cyclicNC-S-CNcyclic alkyl S alkyl 50. A vulcanized rubber derived from rubber or similar material combined with a vulcanizing agent and the compound C0135 Cs 5 CHQ NWS EA CHQ I s 51. A rubber vulcanized under approximately 40 lbs. steam pressure for approximately 10 minutes derived from rubber or similar material combined with 10 parts of zinc oxide, 3 parts of sulphur and 0.1 part of diphenyldimethylthiurammonosulphide.

52. A process of vulcanizing rubber or similar material which comprises combining with the rubber a vulcanizing agent and an accelerator comprising the group m zson,

and vulcanizing the rubber at a temperature below the normal hot vulcanization temperature.

53. A process of vulcanizing rubber or similar material which comprises combining with the rubber a vulcanizing agent and an accelerator comprising the radical NCSCN ii in the presence of a combined metal M, and

vulcanizing the rubber at a temperature below the normal hot vulcanization temperature.

' 54. A process of vulcanizing rubber or similar material which comprises combining with the rubber a vulcanizing agent, an accelerator comprising the radical NCSCN in the presence of a combined metal M, and an amine, and vulcanizing the rubber at a temperature below the normal hot vulcanization temperature.

55. A rubber vulcanized at a temperature below the normal hot vulcanization temperature derived from rubber or similar material combined with a vulcanizing agent and an accelerator comprising the group RCSCR. ii

56. A rubber vulcanized at a temperature below the normal hot vulcanization temperature derived from rubber or similar material combined with a vulcanizing agent and an accelerator comprising the radical NGSCN lit in the presence of a combined metal M.

57. A rubber vulcanized at a temperature below the normal hot vulcanization temperature derived from rubber or similar material combined with a vulcanizing agent, an accelerator comprising the radical NCSCN in the presence of a combined metal M and an amine.

58. The process of treating rubber or similar materials which comprises combiningit with sulphur, diphenyldimethylthiurimmonosulphide, and vulcanizing the rub- 59. A vulcanized rubber derived from rubber or similar materials combined with sulphur, and diphenyldimethylthiurammonosulphide.

60. The process of treating rubber or similar materials which comprises combining it with sulphur, diphenyldimethylthiurammonosulphide and zinc in combination, and vulcanizing the rubber.

61. A vulcanized rubber derived from rubber or similar materials combined with sulphur, diphenyldimethylthiurammonosulphide and zinc in combination.

Signed at New York, New York, this 31st day of March, 1922.

SIDNEY M. CADl/VELL. 

